
void main()
{	
	/*
	// Sepia-Tone Conversion
	float gray = dot(gl_Color.rgb, vec3(0.3, 0.59, 0.11) );
	
	// convert grayscale to sepia
	gl_FragColor = vec4(gray*vec3(1.2, 1.0, 0.8), 1.0);
	*/

	// Grayscale
	float gray = dot(gl_Color.rgb, vec3(0.3, 0.59, 0.11) );
	
	// REplicate grayscale to RGB comp
	gl_FragColor = vec4(gray, gray, gray, 1.0);
}